Anyone wanna build a benchmark Flex app?

That being said, I direct you to the Mozilla Amazon Browser. You need a Mozilla-based browser (what, you're not using FireFox yet?) to view this Rich Internet Application, but I think it's an inspiring piece. Yes, Flash and RIA are not necessarily synonyms. - you can make RIAs with *gasp* other technology.

I wonder if one of the reasons XUL hasn't exploded yet is because it just doesn't have the penetration that Flash does. I wonder how many developers know just what XUL can do. I admit that I'm not even close to a seasoned XUL veteran yet, but in what free time I have I'm exploring leveraging XUL to build cross-platform Flash applications.

Now, why did I mention Flex in the intro paragraph? By now we all know that Flex is a server-side technology to build "rich internet applications" with an XML language (MXML). Combine MXML with a little bit of ActionScript, put it through a compiler, and get a .swf movie that runs inside the Flash player. Thus, the Flash connection.

Now, Flex and XUL are for the most part the same concept. I like XUL better. Here's why... (you don't have to agree.. this is my weblog, so the opinions here are mine and mine alone, unless I manage to convince some of you out there to agree with me...).

The XUL application is VERY responsive. When Flash gets inundated with large amounts of data, it simply dies with a nice little "hey stupid, you tried to do too much in too short amount of time" message. This is bad. Very bad. Once a script times out (typically 15 seconds, but you can adjust that in version 7 .swf files), no more code in the movie can execute. This is equivalent to, say, a core dump in a C program that renders the program useless and doesn't let the user continue.

While Flash is crunching away at data, the UI suffers. There is no threading engine in the Flash VM, so all mouse clicks and such must wait until the code on a particular frame is done. If you've ever looped over 50,000 records, you know what I'm talking about... XUL doesn't have that problem.

Why is this such a problem to begin with? Because if Flash is going to be used for "desktop-like" applications, then it needs to have some certain desktop-like features. The main feature I have in mind is a responsive UI. If Flash is chugging away at data and doing something behind the scenes, the user should still be able to interact with the interface. Anything less than a 1 second response time is no longer "real time" from a user's perspective.

So the XUL application is more responsive than typical Flash RIAs.. big deal.

I think the next major benefit to XUL is that it has a consistent UI, blending in with that of the operating system. In fact, when I launched the application, it opened up in a new window, had a file menu, was resizeable, had an icon-toolbar, etc, and looked just like a desktop application. This is huge as far as users go - there's nothing that gives this application away as being "different" from "regular" desktop applications, and gives the user a seemless overall experience.

Granted, the Flash Halo theme is nice, but some of the components don't behave quite like those of the desktop. Little quirks like this can frustrate users. I don't really care if my combobox "bounces" when it opens. I care that when I tab into it, it behaves just like other comboboxes do in my desktop applications. Maybe the combobox wasn't the best example, but I think you get the idea.

So where am I going with this? Well.. building XUL applications is actually very easy. You use an XML language to define the interface, and you code the application with JavaScript. Guess what, JavaScript and ActionScript are almost one in the same. If you're decent in ActionScript, you should be able to jump right into developing XUL applications without too much effort.

Guess what else. The look and feel of the XUL application is all done through stylesheets. Look at all of the themes available for FireFox... If you're drawn to Flash because you can make applications look different, XUL applications can be skinned too... and easier than trying to skin some of the v2 Flash components.

Anyway, where was I going with this?

I'd like to see a Flex application that behaves just like the Mozilla Amazon Browser. I think a side by side would be useful for the Flash team because they can see how the player stacks up to some other technologies out there. By doing a side-by-side, it should be easy to identify the level of effort involved in creating both XUL and Flex applications (which is easier to code, or are they about the same? which is easier to skin? which is easier to maintain?).

I think the next version of Flash really needs some sort of threading engine to keep playing in "rich internet application" space. It needs to not die when you're trying to do any sort of data processing. The v2 components are new in Flash MX 2004 and I'm sure will continue to improve, but they need to be easier to skin. If we stylesheet was as complete as what XUL supports, that should making skinning much easier. I'm sure there's other "how to make skinning easier" ideas out there, too. And I'm also sure that Macromedia would love to hear them all.

Anyway, I wish I had more free time to build a Flex version of MAB myself.. but I just thought I'd throw the idea out there to see if anyone wants to pick up on it.. Any takers?

Sorry for the long rant.. I was using this XUL application the other day, and it inspried me to post this. I'd like to Flash be able to do this as well as Mozilla does.